/Engine/Source/Runtime/Engine/Classes/Camera/CameraTypes.h
Calculates the projection matrix (and potentially a constrained view rectangle) given aFMinimalViewInfoand partially configured projection data (must have the view rect already set). ConstrainedViewRectangle is only used if the ViewInfo.bConstrainAspectRatio is set.
static void CalculateProjectionMatrixGivenViewRectangle ( const [FMinimalViewInfo](API\Runtime\Engine\Camera\FMinimalViewInfo) & ViewInfo, [TEnumAsByte](API\Runtime\Core\Containers\TEnumAsByte)< enum EAspectRatioAxisConstraint > AspectRatioAxisConstraint, const FIntRect & ConstrainedViewRectangle, [FSceneViewProjectionData](API\Runtime\Engine\FSceneViewProjectionData) & InOutProjectionData )